What are kexec-tools?

31/10/202231/10/2022 | Sarah HendricksonSarah Hendrickson | 0 Comment | 12:00 am

What are kexec-tools?

Kexec is a tool to boot to another kernel from the currently running one. You can perform faster system reboots without any hardware initialization. You can also prepare the system to boot to another kernel if the system crashes.

Should kexec-tools handle reboots?

Reboots via kexec-tools are only supported on SysV init systems. With systemd the only supported init system by now, kexec-tools should no longer ask (during installation) if reboots should be handled by kexec-tools. There should be no user interaction required when installing the package.

How do I enable kexec in Linux?

System kernel config options

  1. Enable “kexec system call” or “kexec file based system call” in “Processor type and features.”: CONFIG_KEXEC=y or CONFIG_KEXEC_FILE=y.
  2. Enable “sysfs file system support” in “Filesystem” -> “Pseudo filesystems.”
  3. Enable “Compile the kernel with debug info” in “Kernel hacking.”:

What is kexec in Linux?

kexec, abbreviated from kernel execute and analogous to the Unix/Linux kernel call exec, is a mechanism of the Linux kernel that allows booting of a new kernel from the currently running one.

How do I reboot with Kexec?

kexec-reboot accepts the following command line arguments:

  1. -i , –interactive. Choose the kernel to stage from a list.
  2. -l , –latest. Stage the latest kernel.
  3. -r , –reboot. Reboot immediately after staging the kernel.
  4. -v , –[no-]verbose. Extra verbosity.

What is Linux Petitboot?

Petitboot is a platform independent bootloader based on the Linux kexec warm reboot mechanism. Petitboot supports loading kernel, initrd and device tree files from any Linux mountable filesystem, plus can load files from the network using the FTP, SFTP, TFTP, NFS, HTTP and HTTPS protocols.

How do I debug a kernel crash dump?

You can also open a dump file after the debugger is running by using the . opendump (Open Dump File) command, followed with g (Go). It is possible to debug multiple dump files at the same time. This can be done by including multiple -z switches on the command line (each followed by a different file name), or by using .

How do I fix end kernel panic not syncing?

Often due to hardware failure… You’ll need to check out /var/log/dmesg and /var/log/syslog to get more info about what actually happened. You should try to boot using a “Live CD”, and then mount the HDD partition that held / and /lib . Then try to restore the libc files.

How do I decode kdump?

How to use kdump for Linux Kernel Crash Analysis

  1. Install Kdump Tools. First, install the kdump, which is part of kexec-tools package.
  2. Set crashkernel in grub. conf.
  3. Configure Dump Location.
  4. Configure Core Collector.
  5. Restart kdump Services.
  6. Manually Trigger the Core Dump.
  7. View the Core Files.
  8. Kdump analysis using crash.

How do I reboot with kexec?

How do I configure Kexec Kdump on RHEL?

CentOS / RHEL 5 : How to Configure kdump

  1. Install the kexec-tools.
  2. Check the file /boot/config-`uname -r`
  3. Modify the system kernel to reserve space for the crash kernel.
  4. Specify where the vmcore should be created.
  5. Update kdump configuration file – /etc/sysconfig/kdump (optional)
  6. Enable the kdump service.

How do I upgrade Petitboot?

Upgrade mode

  1. Download Upgrade image.
  2. Rename the image to spiboot.img.
  3. Paste ‘spiboot.img’ into the file system of the first partition on a micro SD card, not on eMMC.
  4. Power off ODROID-N2.
  5. Insert the card to ODROID-N2.
  6. Toggle the boot mode switch to SPI boot mode.
  7. Power on ODROID-N2.

How do I debug using kdump?

🔗 How to Use Kdump

  1. First, install the kexec-tools , crash and kernel-debuginfo packages using the following command line.
  2. Fedora 34 and older: Use kdumpctl estimate to determine the recommended crash kernel size to use.
  3. Fedora 35 and newer: Use kdumpctl reset-crashkernel .

How do you analyze a Vmcore file?

To quickly view the contents of vmcore-dmesg. txt, open the file in a text editor or grep for the word crash with the cat vmcore-dmesg. txt | grep -i crash command. As you can see, SysRq triggered a crash when you issued the echo commands.

How do I resolve kernel panic in Linux?

7 Steps to Troubleshoot RHEL-7 Kernel panic error in Linux:

  1. Boot the system in rescue mode.
  2. Log in using the root account.
  3. Navigate to /boot.
  4. See if initramfs.img file is available (If it is available, it must be corrupted.
  5. find kernel version (uname -r)
  6. mkinitrd initramfs-kernel_version.img kernel_version.

How do you stop kernel panic?

  1. Restart.
  2. Go to advanced menu and then click on ‘e'(edit the boot parameters)
  3. Go down to the line which starts with linux and press End.
  4. Press space.
  5. Add the following at the end -> kernel.panic=1.
  6. Press F10 to restart.

How do I analyze a crash dump file in Linux?

How do I update Petitboot Odroid N2?

How do I fix kernel panic error?

How do I debug kernel in oops?

cd to your directory of your kernel tree and run gdb on the “.o” file which has the function sd_remove() in this case in sd.o, and use the gdb “list” command, (gdb) list *(function+0xoffset), in this case function is sd_remove() and offset is 0x20, and gdb should tell you the line number where you hit the panic or oops …

How do I troubleshoot kernel panic error in Linux?

How do I debug a core dump?

You just need a binary (with debugging symbols included) that is identical to the one that generated the core dump file. Then you can run gdb path/to/the/binary path/to/the/core/dump/file to debug it. When it starts up, you can use bt (for backtrace) to get a stack trace from the time of the crash.

How do I troubleshoot kernel panic in Linux?

How do I fix a kernel panic on my Mac?

If the faulty software is not identified and your Mac continues to experience kernel panics, try the following: Restart your Mac in safe mode. If it successfully starts up in safe mode, choose Apple menu > App Store, click Updates, then install any available updates.

How do I debug a core file in dbx?

Set the dbx environment variable core_lo_pathmap to on. Use the pathmap command to tell dbx where the correct libraries for the core file are located. Use the debug command to load the program and the core file. If you are not exporting the root partition of the core-host, you must copy the libraries by hand.

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